We present the HoloVizio system design and give an overview about Holografika's approach to the 3D displaying. The patented HoloVizio technology uses a specially arranged array of optical modules and a holographic screen. Each point of the holographic screen emits light beams of different color and intensity to the various directions. The light beams generated in the optical modules hit the screen points in various angles and the holographic screen makes the necessary optical transformation to compose these beams into a perfectly continuous 3D view. With proper software control, light beams leaving the pixels propagate in multiple directions, as if they were emitted from the points of 3D objects at fixed spatial locations. We show that the direction selective light emission is a general requirement for every 3D systems and provide quantitative data on the FOV, on the angular resolution, determining field of depth of the displays, affecting the total number of light beams necessary for high-end 3D displaying. We present the results with the 10 Mpixel desktop display and the 50Mpixel large-scale system. We cover the real-time control issues at high pixel-count systems with the HoloVizio software environment and describe concrete 3D applications developed in the frame of European projects.